Metformin-associated lactic acidosis presenting as an ischemic gut in a patient who then survived a cardiac arrest: a case report

A case report of metformin-associated lactic acidosis

Key Clinical Message

Metformin-associated lactic acidosis is a rare but serious complication in patients with type 2 diabetes, especially those with multiple health conditions. Prompt recognition and treatment, including potential renal replacement therapy, are crucial for managing severe acidosis and improving patient outcomes.

Abstract

Metformin (MTF) is commonly prescribed as a first-line treatment for diabetes, effectively preventing microvascular and macrovascular complications. However, metformin-associated lactic acidosis is a rare yet severe complication, associated with a mortality rate of up to 50%. We encountered a case involving a 73-year-old woman with type 2 diabetes, mental illness, and hypothyroidism, who developed life-threatening lactic acidosis while on metformin therapy. Upon presenting to the emergency department with complaints of weakness, nausea, and decreased urination for 5 days, she also reported abdominal pain and shortness of breath. Hypotension was noted with a blood pressure of 80/50 mmHg. Initial laboratory results revealed severe acidosis, prompting discontinuation of MTF. Despite resuscitation efforts and vasopressor therapy, severe acidemia persisted, leading to the initiation of renal replacement therapy. Following treatment with continuous renal replacement therapy, her acidemia resolved, and she was discharged from the hospital on the sixth day without complications, with normal kidney function.

Metformin-Associated Lactic Acidosis in an Older Adult: A Case Report and Review

Metformin is a widely prescribed medication for the management of type 2 diabetes. It is known to have a high safety index; however, it can cause serious adverse effects such as lactic acidosis, particularly in patients with chronic kidney disease. Elderly patients are at higher risk of developing metformin-associated lactic acidosis (MALA) due to aging kidneys. We present an 82-year-old male with a past medical history of diabetes, stage 2 chronic kidney disease, atrial fibrillation on apixaban, stroke, and chronic stage 4 sacral decubitus ulcer who was sent to the emergency department (ED) for altered mental status. He was admitted to the intensive care unit for the management of septic shock, pulseless electrical activity (PEA) cardiac arrest, and acute hypoxemic respiratory failure requiring intubation. Laboratory tests showed lactic acidosis and anion gap metabolic acidosis in the absence of an infectious source. The patient had chronic kidney disease with acute renal failure on metformin. He was diagnosed with MALA. This case highlights the potential risks associated with metformin use in older adults with chronic kidney disease and acute kidney injury from infections, dehydration, and decreasing oral intake due to acute illness, aging, or dementia. There are expected physiological changes in the aging kidney, including cellular dysfunction and nephrosclerosis, that can cause unexpected kidney injury in older adults, causing their estimated glomerular filtration rate (eGFR) to drop acutely. Age-related changes in renal function and decreased clearance of drugs place elderly patients at higher risk of developing MALA. Guidelines for reducing or deprescribing metformin can be considered in older adults. This could prevent morbidity, mortality, and adverse outcomes in frail older adults with diabetes.

Surviving cardiac arrest from severe metformin-associated lactic acidosis using extracorporeal membrane oxygenation and double continuous venovenous haemodialysis

Metformin-associated lactic acidosis (MALA) is a serious condition with high mortality. This case describes a man in the mid-60s with diabetes mellitus type 2 treated with metformin developing MALA 4 days after coronary stenting for non-ST-elevation myocardial infarction. He presented acutely with severe abdominal pain, a lactate of 19 mmol/L and pH 6.74. Despite treatment for MALA, he went into refractory cardiac arrest and was connected to venoarterial extracorporeal membrane oxygenation (VA-ECMO). He suffered a massive haemothorax due to perforation of the right atrial appendage. It was repaired through a sternotomy while being given massive blood transfusions. The following days, he was on VA-ECMO and double continuous venovenous haemodialysis (CVVHD). He survived with only mild paresis of the left hand. VA-ECMO should be considered a rescue therapy alongside treatment with CVVHD in case of cardiac arrest due to severe MALA.

Continuous extracorporeal clearance in metformin-associated lactic acidosis and metformin-induced lactic acidosis: a systematic review

INTRODUCTION

Metformin poisoning with lactic acidosis is an uncommon yet clinically serious condition related to the inhibition of normal aerobic metabolism. Toxicity may occur after an acute overdose although it is much more common after a systemic insult, such as acute kidney injury, in the setting of chronic use. Hemodialysis is currently the preferred extracorporeal treatment modality (Grade 1D evidence) although some patients may be too hemodynamically unstable to tolerate it. Continuous renal replacement therapy is considered an alternative if hemodialysis is unavailable but an evaluation of survival amongst this specific treatment class is lacking.

OBJECTIVES

To assess overall survival and provide an updated review of the toxicokinetic elimination parameters of patients receiving continuous renal replacement therapy for metformin poisoning.

METHODS

A comprehensive search was performed using the EMBASE and MEDLINE libraries from inception until November 30, 2021. Data was extracted and findings were summarized. Toxicokinetic parameters were analyzed and confirmed for accuracy when data permitted.

RESULTS

Eighty-three reports met inclusion criteria. These consisted of only low-quality evidence including 75 case reports, four case series, and four descriptive retrospective reviews. Overall survival among patients suffering from metformin toxicity who received continuous extracorporeal treatment was 85.8%. When stratified between metformin-induced lactic acidosis and metformin-associated lactic acidosis, survival was 75.0% and 87.4%, respectively. Available continuous renal replacement therapy toxicokinetic parameters were quite heterogeneous. Errors in previously published toxicokinetic calculations were noted in only two instances. The overall average and median peak metformin concentrations were 70.5 mg/L and 41.9 mg/L, respectively. The average and median extracorporeal clearance rates were 39.0 mL/min and 42.1 mL/min (range 9.0-58.7 mL/min). The average and median elimination half-life parameters were 27.5 h and median 23.0 h. Elimination half-life ranged from seven to 74 h. There was no meaningful relationship between peak metformin concentration and continuous extracorporeal treatment half-life at lower concentrations, though at very high concentrations (over 200 mg/L), there was a trend towards a half-life below 20 h. There is insufficient data to robustly evaluate overall survival in relation to the extracorporeal clearance rate. Finally, there was no relevant relationship between maximal lactate concentration and survival, nor nadir pH and survival, for patients with either type of metformin toxicity.

CONCLUSIONS

This retrospective systematic analysis of published cases treating metformin related lactic acidosis with continuous renal replacement therapy notes an overall slightly greater survival percentage compared to previous publications of individuals requiring any modality of renal replacement therapy. Because of publication bias, these results should be interpreted with caution and serve as hypothesis generating for future research. Prospective study focusing on the most clinically meaningful endpoint - survival - will help elucidate if continuous modalities are non-inferior to intermittent hemodialysis in metformin toxicity.

A patient with severe metformin-associated lactic acidosis complicated by acute coronary syndrome: a case report

Introduction

Metformin-associated lactic acidosis (MALA) is a rare but life-threatening condition. Here, we report the outcome of a patient with MALA complicated by acute coronary syndrome.

Case presentation

A 47-year-old obese woman of Caucasian ethnicity was admitted for syncope and tachypnea with Kussmaul breathing. She had a type-2 diabetes and was on oral antidiabetic therapy. Hemoglobin A1c was 6.6%. On admission, a severe acute kidney injury (serum creatinine: 1251 µmol/L) with hyperkalemia (7.5 mmol/L) and severe lactic acidosis (ph:7.042, bicarbonate: 9.9 mmol/L, partial pressure of carbon dioxide: 21.8 mmHg, lactate: 20.0 mmol/L) was found. Despite bicarbonate therapy, ph further decreased. Within 2.5 h of admission, a temporary hemodialysis catheter was placed, and one session of a high-efficiency hemodialysis was performed. 8 h after admission, a continuous venovenous hemodiafiltration was initiated and maintained for 2 days. The metformin therapy was stopped. Supplemental oxygen, intravenous catecholamines (4 days) and antibiotic therapy (7 days) were applied. During this therapy of lactic acidosis, an acute coronary syndrome evolved by day 2 after admission and resolved by day 5 in hospital. After recovery, the patient was transferred to a general ward on day 7 and left the hospital on day 11. By discharge, both the acute kidney injury and the acute coronary syndrome were reversible.

Conclusion

In the patient with MALA complicated by acute coronary syndrome, the combination of a high-efficiency hemodialysis and, consecutively, continuous venovenous hemodiafiltration led to a favorable outcome.

Metformin-Associated Lactic Acidosis: A Case Report and Review

Metformin is widely prescribed as the first-line medication for type II diabetes mellitus. While the gastrointestinal side effects of metformin such as nausea, vomiting, diarrhea, and heartburn are quite common, one dangerous side effect of metformin, lactic acidosis, is extensively discussed yet rarely reported. Here, we discuss a 53-year-old female with type II diabetes mellitus who presented to an emergency department (ED) with chief complaints of dizziness and lightheadedness. The patient had chronic kidney disease (CKD) with a baseline estimated glomerular filtration rate (eGFR) of 45 mL/minute/1.73 m². Initial laboratory results showed acute kidney injury (AKI) with hyperkalemia and lactic acidosis of 20 mmol/L. The patient was admitted to the ICU requiring emergent dialysis. Later, she was diagnosed with metformin-associated lactic acidosis (MALA). Her AKI and lactic acidosis subsequently improved. Metformin-associated lactic acidosis (MALA) is a rare but serious side effect of metformin. It is primarily reported in patients with chronic renal failure; therefore, it should be used with caution in these patients. Renal replacement therapy (RRT) is the critical management option for patients with MALA. Because of this, physicians prescribing metformin should carefully monitor all patients and assess the risk of developing severe side effects.

Molecular dynamics of estrogen-related receptors and their regulatory proteins: roles in transcriptional control for endocrine and metabolic signaling

Estrogen-related receptor (ERR) is a member of the nuclear receptor (NR) superfamily and has three subtypes α, β, and γ. Despite their strong homology with estrogen receptor (ER) α, ERRs cannot accommodate endogenous hormones. However, they are able to regulate gene expression without ligand binding. ERRα and ERRγ orchestrate the expression of genes involved in bioenergetic pathways, while ERRβ controls placental development and stem cell maintenance. Evidence from recent studies, including clinical research, has also demonstrated close associations of ERRs with the pathophysiology of hormone-related cancers and metabolic disorders including type 2 diabetes mellitus. This review summarizes the basic knowledge and recent advances in ERRs and their associated proteins, focusing on the subcellular dynamics involved in transcriptional regulation. Fluorescent protein labeling enabled monitoring of ERRs in living cells and revealed previously unrecognized characteristics. Using this technique, we demonstrated a role of ERRβ in controlling estrogen signaling by regulating the subnuclear dynamics of ligand-activated ERα. Visualization of ERRs and related proteins and subsequent analyses also revealed a function of ERRγ in promoting liver lactate metabolism in association with LRPGC1, a recently identified lactic acid-responsive protein. These findings suggest that ERRs activate unique transregulation mechanisms in response to extracellular stimuli such as hormones and metabolic signals, implying an adaptive system behind the cellular homeostatic regulation by orphan NRs. Control of subcellular ERR dynamics will contribute toward the development of therapeutic approaches to treat various diseases including hormone-related cancers and metabolic disorders associated with abnormal ERR signaling pathways.

The Association between Metformin Therapy and Lactic Acidosis

INTRODUCTION AND OBJECTIVES

There is increasing evidence to suggest that therapeutic doses of metformin are unlikely to cause lactic acidosis. The aims of this research were (1) to formally evaluate the association between metformin therapy and lactic acidosis in published case reports using two causality scoring systems, (2) to determine the frequency of pre-existing independent risk factors in published metformin-associated lactic acidosis cases, (3) to investigate the association between risk factors and mortality in metformin-associated lactic acidosis cases, and (4) to explore the relationship between prescribed metformin doses, elevated metformin plasma concentrations and the development of lactic acidosis in cases with chronic renal impairment.

METHODS

A systematic review was conducted to identify metformin-associated lactic acidosis cases. Causality was assessed using the World Health Organisation-Uppsala Monitoring Centre system and the Naranjo adverse drug reaction probability scale. Compliance to dosing guidelines was investigated for cases with chronic renal impairment as well as the association between steady-state plasma metformin concentrations prior to admission.

RESULTS

We identified 559 metformin-associated lactic acidosis cases. Almost all cases reviewed (97%) presented with independent risk factors for lactic acidosis. The prescribed metformin dose exceeded published guidelines in 60% of cases in patients with impaired kidney function. Metformin steady-state plasma concentrations prior to admission were predicted to be below the proposed upper limit of the therapeutic range of 5 mg/L.

CONCLUSIONS

Almost all cases of metformin-associated lactic acidosis reviewed presented with independent risk factors for lactic acidosis, supporting the suggestion that metformin plays a contributory role. The prescribed metformin dose, on average, exceeded the dosing recommendations by 1000 mg/day in patients with varying degrees of renal impairment but the predicted pre-admission plasma concentrations did not exceed the therapeutic range.

Metformin-Associated Lactic Acidosis: A Case Report

A 54-year-old woman with type 2 diabetes mellitus, hypertension, and peripheral vascular disease developed life-threatening lactic acidosis during treatment with metformin for type 2 diabetes. The woman received metformin at 1000 mg orally twice a day for type 2 diabetes. She presented to our emergency department with a 3-day history of severe watery diarrhea, nausea, and vomiting. Her grandson whom she cared for had gastroenteritis several days prior to the onset of her symptoms. She was confused and hypotensive with a blood pressure of 70/39 mmHg. Her initial laboratory findings were remarkable with an arterial blood gas pH 6.57, HCO[Formula: see text] 2 mEq/L, anion gap 30 mmol/L, and lactate 16.3 mmol/L. She was diagnosed with severe lactic acidosis. Metformin was discontinued. Upon arrival in the emergency department, she became unresponsive and experienced a pulseless electrical activity cardiac arrest. After resuscitation, her severe acidemia persisted despite aggressive intervention with volume resuscitation and vasopressors, leading to the initiation of renal replacement therapy. After multiple dialysis treatments, her severe acidemia resolved. Serum metformin concentration from presentation ultimately returned to 42 mcg/mL (therapeutic concentration: 1-2 mcg/mL). She was discharged from the hospital on day 15 without any neurologic complications. A Naranjo assessment score of 8 was obtained, indicating a probable relationship between the patient's lactic acidosis and her use of the suspect drug.

Metformin-associated lactic acidosis mimicking ischaemic bowel

Metformin-associated lactic acidosis (MALA) is a rare complication among patients who are diabetic, commonly presenting with non-specific findings, and developing mostly among those with other risk factors for lactic acidosis. We report the development of MALA in a 67-year-old man with diabetes who presented with progressive abdominal pain and bloody diarrhoea. On presentation the patient was in shock, with signs suggestive of peritonitis, and with severe lactic acidosis, renal failure and non-specific findings on abdominal CT. Neither the patient nor family could provide details of his home pharmaceuticals. Circulatory resuscitation with intravenous crystalloids and vasopressors was commenced, along with empiric broad-spectrum antibiotics. Emergent laparotomy did not show pathological findings. Emergent haemodialysis, initiated postoperatively, resulted in rapid resolution of shock and lactic acidosis. A list of patient's medications, provided afterwards by the family, included metformin. Microbiological studies remained negative and renal function normalised by the time of patient's hospital discharge after 9 days.

Metformin-associated lactic acidosis: Current perspectives on causes and risk

Although metformin has become a drug of choice for the treatment of type 2 diabetes mellitus, some patients may not receive it owing to the risk of lactic acidosis. Metformin, along with other drugs in the biguanide class, increases plasma lactate levels in a plasma concentration-dependent manner by inhibiting mitochondrial respiration predominantly in the liver. Elevated plasma metformin concentrations (as occur in individuals with renal impairment) and a secondary event or condition that further disrupts lactate production or clearance (e.g., cirrhosis, sepsis, or hypoperfusion), are typically necessary to cause metformin-associated lactic acidosis (MALA). As these secondary events may be unpredictable and the mortality rate for MALA approaches 50%, metformin has been contraindicated in moderate and severe renal impairment since its FDA approval in patients with normal renal function or mild renal insufficiency to minimize the potential for toxic metformin levels and MALA. However, the reported incidence of lactic acidosis in clinical practice has proved to be very low (<10 cases per 100,000 patient-years). Several groups have suggested that current renal function cutoffs for metformin are too conservative, thus depriving a substantial number of type 2 diabetes patients from the potential benefit of metformin therapy. On the other hand, the success of metformin as the first-line diabetes therapy may be a direct consequence of conservative labeling, the absence of which could have led to excess patient risk and eventual withdrawal from the market, as happened with earlier biguanide therapies. An investigational delayed-release metformin currently under development could potentially provide a treatment option for patients with renal impairment pending the results of future studies. This literature-based review provides an update on the impact of renal function and other conditions on metformin plasma levels and the risk of MALA in patients with type 2 diabetes.

Non-occlusive Mesenteric Ischemia with Diabetic Ketoacidosis and Lactic Acidosis Following the Administration of a Sodium Glucose Co-transporter 2 Inhibitor

We herein describe a patient with non-occlusive mesenteric ischemia (NOMI) potentially associated with the administration of a sodium glucose co-transporter 2 (SGLT2) inhibitor. A 60-year-old man with type 1 diabetes was transferred to our hospital due to vomiting and respiratory distress. He was treated with insulin, metformin and a SGLT2 inhibitor, which had recently been added. He was diagnosed with intestinal ischemia complicated by diabetic ketoacidosis and lactic acidosis. Urgent exploratory surgery was performed, and the gangrenous bowel was resected. Histological findings confirmed the diagnosis of NOMI. The administration of SGLT2 inhibitors therefore requires certain exceptions for type 1 diabetes and cautious monitoring for the occurrence of these possible adverse effects.

Hyperlactatemia and the Outcome of Type 2 Diabetic Patients Suffering Acute Myocardial Infarction

Background. Increased lactate production is frequent in unregulated/complicated diabetes mellitus. Methods. Three groups, each consisting of 40 patients (type 2 diabetics with myocardial infarction, DM+AMI, nondiabetics suffering myocardial infarction, MI, and diabetics with no apparent cardiovascular pathology, DM group), were tested for pH, serum bicarbonate and electrolytes, blood lactate, and CK-MB. Results. Blood lactate levels were markedly higher in AMI+DM compared to MI group (4.54 ± 1.44 versus 3.19 ± 1.005 mmol/L, p < 0.05); they correlated with the incidence of heart failure (ρ = 0.66), cardiac rhythm disorders (ρ = 0.54), oxygen saturation (ρ = 0.72), CK-MB levels (ρ = 0.62), and poor short-term outcome. Lactic acidosis in DM+AMI group was not always related to lethal outcome. Discussion. The lactate cutoff value associated with grave prognosis depends on the specific disease. While some authors proposed cutoff values ranging from 0.76 to 4 mmol/L, others argued that only occurrence of lactic acidosis may be truly predictive of lethal outcome. Conclusion. Both defective glucose metabolism and low tissue oxygenation may contribute to the lactate production in diabetic patients with acute myocardial infarction; high lactate levels indicate increased risk for poor outcome in this population comparing to nondiabetic patients. The rise in blood lactate concentration in diabetics with AMI was associated with increased incidence of heart failure, severe arrhythmias, cardiogenic shock, and high mortality rate.